support autoconf 2.63

lower autoconf requirement from 2.69 to 2.63. The only changed needed to
support this was to change AC_CHECK_HEADER_STDBOOL to AC_HEADER_STDBOOL.

2.63 didn't have AC_CHECK_HEADER_STDBOOL and AC_HEADER_STDBOOL checks
basically the same thing.
build instructions for CentOS/RHEL/Oracle Linux 6.3
build gearbox workers and run their tests

Modified Makefile.am to compile the delayDaemon and workerGearbox

The tests in workers/t/gearbox assumed they were being executed from
the same directory they lived in.  This was true when they were compiled
using recursive make.  Since they reference config files which reference
relative directories, I just did a chdir at the beginning of test.

I made small changes to valid-schemas.t to be compatible with the newer
version of boost filesystem that's in boost >= 1.49.
build test workers
updated BUILD.OSX to work with 10.8 Mountain Lion
build apache module mod_gearbox

I had to update mod_gearbox.cc to undefine some PACKAGE_*
that conflicted.  It looks like this is caused by apache's
ap_config_auto.h and gearbox's config.h both defining them

I imported m4/ax_with_apxs.m4 that I found from
https://github.com/timfel/mod_auth_openid/ that looks to be
originally copied from modpython's source.

I'm not sure if I need the apr-1-config stuff.  It may be
unnecessary.
Merge pull request #3 from jaybuff/build-workers-and-apache

Build workers and apache